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Hypersonic vehicles have strong maneuverability, and the method of trajectory prediction is different from traditional aircrafts. The current research on hypersonic vehicle trajectory prediction is usually aimed at the full trajectory prediction, and there are few methods for hypersonic vehicle trajectory prediction in specific scenes. In this paper, aiming at the scene that hypersonic vehicle be not observed in the blind area of land-based radar, a trajectory prediction method of hypersonic vehicle is proposed, which is realized by predicting the control quantity. According to the constraint characteristics, aerodynamic characteristics and motion characteristics, the characteristic function is established. And on the basis of the priori information from the observed data, the conditional random field model is established to predict the control quantity. The trajectory in the blind area is calculated according to the predicted control quantity. Finally, the effectiveness and feasibility of the trajectory prediction method proposed in this paper are verified by case study.

In order to improve the attitude measurement accuracy of the stratospheric airship, a stochastic process of damped oscillation autocorrelation is proposed to model the attitude angular velocity of the stratospheric airship, and the state transition matrix and the process noise covariance matrix of the model are derived. Based on this, the Kalman filter algorithm is used to correct the attitude angle measurement of the stratospheric airship. Finally, the model is compared with Singer model, Jerk model and sinusoidal correlation model by simulation experiment and the influence of parameter selection on model effect is analyzed. The results demonstrate the effectiveness and advantages of the proposed model in correcting the attitude angle of the stratospheric airship.

recently, with the more extensive deployment of Wireless Local Area Networks (WLAN), and the growing population of mobile users, the unstable handover problem in wireless network services receives more and more attention. Since users expect the continuity of services while roaming, IEEE 802 family defines the standard IEEE 802.11r (Fast BSS Transition) to reduce the interrupted time of services to the minimum. Supposing users use IEEE 802.11r to execute the pre-authentication process with all Access Points, there will be too many authenticated messages. Therefore, an IEEE 802.11rbased algorithm is proposed to avoid the pre-authentication process with all APs. In order to reduce the pre-register APs, we first of all divide the coverage of the APs into four regions according to the RSSI. Second, to figure out more accurate APs, we dynamically adjust the region. Third, if the mobile device cannot find the AP of each region, we further modify the region. Finally, we pick up an AP to execute the preauthentication each region. With the four above-mentioned considerations proposed in this algorithm, we are able to make use of roaming more effectively.

Aiming at solving the problem of detection performance degradation of CA-CFAR and OS-CFAR in the circumstance of multi-targets and strong interference, a CFAR whose selection of reference samples is based on statistics of the CUT (Cell-Under-Test) is presented. Simulation shows that this CFAR suffers a small CFAR loss compared to CA-CFAR in homogeneous environment, and performs robustly against interferers in a non-homogeneous environment.